Phonographic recording or reproducing apparatus.



T. A. EDISON. PHONOGRAPHIG REGORDING ORREPRODUGING APPARATUS. APPLICATION I'ILEDMAR. 16, 1907. 1 ()78 264 I Patented Nov. 11, 1913.

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T. A. EDISON. I PHONOGRAPHIC RECORDING OR R EPRODUOING APPARATUS. APPLICATION FILED MAR. 16, 1907.

1,078,264, 7 Patented N0v.11, 1913.

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Specification of Letters .Patent.

Patented Nov. 11, 1913.

\ Application filed March 16, 1907. Serial No. 362,597.-

To all whom it may concern} Be it known that I, Tnom as ALVA Eorson,

a citizen of the United States, and a resident I of Llewellyn Park, Orange, in the county of,

Essex and State of New Jersey, have invented certain new and useful I p-rovements 1n Phonographic Recording or Reproducing Apparatus, of which the following a de-.

scription.

My invention relates to/irnprovements in recording or reproducingzga;I apparatus for phonographs or other talkingmachines, but the improvements are particularly directed to reproducing apparatus,

With phonographic reproducing apparatus as now made, the diaphragm which is rigidly clumped at its periphery, comprises a single disk corrugated so as to be as stiff as possible, ora series of disks of gradually reduced diameters. With such a diaphragm the limit of amplitude is comparatively slight, since in vibrating to one side or the' other of the medial line the diaphragm is not only flexed butit undergoes stretching and contraction as it recedes from or apprQaches the medial line. Furthermore, the resistance of the diaphragm to the vibrating efl'ect enormously increases as the diaphragm is distorted out of its normal plane, For these Ira-sons any attempts to increase the loudness ofphonogra-phic reproduction by increasing the amplitude have been 1111-.

successful, for the reason that to materially increase the amplitude of vibration would impose an enormous increase in the wear of the record surface.

floatin weights are used that are as heavy as 81 7 Furthermore, I find that even under existing conditions, where employed without imposing objecw 'tionable wear on the record, the weight static column of air is susceptible of vibrations of relatively enormous amplitude and wherein the power necessary to efl'ect such vibrations remains practically constant throughout the entire movement.

A further object'is to provide a recording or reproducing apparatus in which a compensating weight maybe 'used of great mass, so as to be unresponsive to any of the vibrations of the record but maintaining the stylus in correct relation to the surface regardless of mechanical variations oreccentricities therein, and at the same time the said weight, notwithstanding its great mass, will not lmpose any undue wear on the waxlike material. I

To this endthe invention consists, in a. broad sense, of employing as a means for setting upvibrations in a static column of air a vibrating piston instead of 21 dia phragm, the piston fitting very closely but not touching the bore of the casing in which it operates, connected to 'the stylus so that the two will move in'unison, and combined with suitable elastic tension devices for maintaining the stylus in proper engage ment with the recording surface or the record as the case may be, Such a vibrating piston is made as light as possible so as to reduce momentum and inertia to a minimum, and it is'therefore preferably formed of thin sheet aluminum or magnesium (preferably the latter) having a depending flange, with its body formed with concentric corru gations and preferably rovided with radial ribs, sons to be assti as possible. With these devicesI contemplate using a compensatingWeight of greater mass than is customary, which is supported on the record itself preferably by an anti-friction roller, and I pivot the stylus lever to this weight in such position that the stylus will be in line with that part of the weight that bears on the record, such as the roller referred to, so that the desired relation of the stylus and the weight will be always maintained.

In order that the invention may be better understood, attention is directed to the accompanying drawing forming part of this specification, and in which provements in their preferred form,--and showing the use of a compensating weight; Fig. 2'is a bottom view of the same; F 1g.

'3 is an enlarged detail view showing the compensating weight and the connection With the sty us lever; Fig. 4 is an enlarged detail view showing the adjustment for the tension mechanism; Fig. 5'is a cross sectional view similar to Fig. 1, showing the apparatus without the compensating weight, as it may beused if the records are sufficiently true; Fig. 6 is an enlarged View showin the construction of diaphragm, and Fig. 7 1s a bottom view of the diaphragm.

In all of the above views corresponding parts are represented by the same reference numerals. v v I The casing 1 is made preferably of aluminum and is supported in any suitable way with respect to, andis fed longitudinally o the record 2. The casing 1 is formed with I a bore 3, turned very true andfrom which leads the air passage 4, connected to the usual horn.. .WGIlKlIlg' closely. within the bore 3, is a piston 5 formed with a depending flange 6 and preferabl also a horizontal rim 7, and'themain portlon of said piston is formed Wlth' concentric corrugations as shown, and preferably-with radial ribs '8,

so as to be as stiifas ossible.. Preferably the piston is made of hin sheet aluminum or magnesium, while the ribs 8, three or four in number, are made of the same metal secured in place by means of shellac or other appropriate cement. The fit of the piston 5 within the bore 3 is very close, .say within .0005 of an inch, so that while the piston is free to move it does not touch the jwallsof the casing.

Secured to-the center of the piston 5 is an aluminum or magnesium tube 9, working in a bearing inthe casing 1, as shown and guided by a bearing in the bridge piece 10 secured to the under side of the casing. Preferably the holes for the screws by which the bridge 10 is held in place, are larger than the screws so that after. the piston has been properly centered the bridge may be secured in place. The-lower end of the tube 9 is formed with a small head 11 to is employed in the manufacture of cer- -tain Swiss' watches. The outer end of the stylus lever-13 is curved so that as the lever" moves the. piston will be actuated in a straight line and will not become jammed in its bores-The stylus 14 is'connected at the the record itself. At the same time any other'end of the stylus'lever 13, and the fulcrum of the stylus lever is preferably nearer the stylus so that the movement of the stylus will be amplified at the piston and increased amplitude will thereby be secured.

The stylus'lever is preferably formed of metallic aluminum. At its upper end the tube 9 is. provided with a small, head 15 through which eirtends a pin with which a spring 16 is connected. The-spring 16 is through the yoke 19 and is preferably square so as not to turn therein. Nuts 20 effect the adjustment of the rod 18. It will be understood of course that instead of a rubber spring, any other kind-of a spring may be employed. The spring 16 supports the piston 5 and imposes an upward tension on the stylus lever 13 to keep the. stylus always in close engagement with the record surface, and at the same time maintains a stress on the connections between the piston and the stylus lever so as to prevent lost motion. Since the piston is free to occupy any position within the bore 3,'it will, by

means of the spring 16, be automatically brought to the desired medial point on each side of which it will be vibrated by the ,vi brations of the stylus and to an amplified extent depending obviously upon, the levera e.

W en the records are sufiiciently true for the purpose and are substantially concentric throughout, the styluslever 13 as shown in Fig. 5, may be pivoted on an arm 21,depending. from the casing 1, the tension mechanism always "keeping the stylus in engagement with the record, notwithstanding small variations in the record, but' under ordinary commercial conditionsa compeneating weight is desirable. This weight 22 1s plvoted from an arm 23 depending from the casing 1 with's'ufiicient lost motion to permitthe stylus to automatically track' the record, and the weight. is formed with depending lugs 24 between which the stylus lever is pivoted. By reason of the fact that the vibrating piston is susceptible of relatively 'greatmovement within the casing, so as to occupy a desired medial position 'in which, it may be drawn by the spring 16, it

is no longer necessarywith the improved device to float the compensating weight and to practically sustain it from the stylus itself. On the contrary the weight may rest directly on therecord, being su ported by an anti-friction roller 25 arrange in line with the stylus and of suflicient width of .face to bridge-over a number of the record grooves, so that nojwear will be imposed on the record, nor will the weight be affected by the minute vibrations which! characterize mechanical eccentricities or variations in the record as a whole, will causethe com ensating weight to rise and fall'carrying t e fulcrum of the stylus lever with the same, and permitting the stylus to be always mainimam tained in proper engagement with the record surface, notwithstanding very considerable variations in the record.

In the present application I shall not specifically claim the form of device shown in Fig. 5, as I propose. in a separate applica tion, Serial 'No. 862,596, filed concurrently clude the form of herewith, to claim that-construction specifically. Certain of the claims 'of this case,

however, which may not, belimited to the compensating weight, will necessarily inevice shown in Fig.- 5.

Ido not claim herein broadly the suggestion of a diaphragm unsupported at its edge or, in other Words, a vibrating piston operating to set up vibrations in a static column of air, because that construction is broadly disclosed and claimed in my Patent No.

v 500,281 of June 27, 1893. With my prior patent, however, the stylus was maintained in engagement with therecord solely by the weight of the piston and the parts connected therewith, and if such piston and connected parts were .made light enough to be readily responsive to the sound vibrations, the proper engagement would not be maintained between the stylus and the record; while if made heavy enough to hold the stylus in en-" gagement with the record, the inertia would be so great as to make the device but slightly responsive. to the variations of the record. For a successful apparatus some independent elastic tension device is necessary 'to maintain the stylus in proper engagement with the record. I

Having now described my invention, what I claim as new therein and desire to secure 1 by Letters Patent-,is as follows:

tension, substantially as and for the purposes ,set forth.

2. A phonographic recording'or' reproducing apparatus employing in combination a casing, a vibrating piston freely mounted therein, a stylus lever mounted below the casing, a connection between the piston and one end of the stylus lever, a stylus at the other end of thest-ylus lever and a tension device above the piston for imposing an upwardly acting elastic tension thereon, substantially as and forthe purposes set forth.

3. A phonographic recording or reproducing apparatus employing in combination a casing, a vibrating piston freely mounted therein, a stylus lever mounted below the casing, a connection between the piston and one end of the stylus lever, a stylus at the other end of the stylus lever, a tension device above the piston for imposing an'up- Wardly acting elastic tension thereon, and means for, adjusting the tension device, substantially as and for the purposes set forth.-

4. In a phonographic recording or repro ducing apparatus, the combination of a casing, a vibrating piston freely mounted therein, a stylus leverlbelow the casing, a metal spring connecting the piston with the stylus lever and a'tension device above the piston for exerting an upwardly acting elastic tension thereon, substantially as and for the purposes set forth. 4 v

5. In a phonographic recording or reproducing device,- the combination with a casing, a vibrating piston freely mounted therein, an elastic tension device above the piston for exerting upward stress thereon, a stylus lever having a curved end mounted below the casing and a connection between the curved end of the styluslever'and the piston, substantially as and for the pur poses setvforth. v

6. In a phonographic recording or reproducing apparatus, the combination with a casing, a vibrating piston freely mounted therein and adapted to impart sound vibra tions to the static column of air in said casing, a compensating weight below the easing, a stylus lever pivoted to the compensating weight, connections betweenthe stylus lever and the piston and means for guiding the movement of saidgpiston in a straight line parallel to the bore of the casing in which it is mounted, and an elastic tension device for exerting elastic pressure between the stylus and the record or recording surface, substantially as and for the purposes set forth. I

7.. In a phonographic recording or reproducing apparatus, the combination of a casing, a vibrating piston freely mounted therein, a stylus lever, below the casing, a stylus mounted on said lever on one side of the fulcrum thereof, connections from said piston to said lever on the other side of the fulcrum,'including rigid means and flexible means, and means for guiding the rigid means to prevent movement of said piston other than in a straight line parallel tot-he bore of the casing in which it is mounted, substantially as set forth,

8. In a phonographic recording or reproducing device, the combination of a casmg, a vibrating piston freely mounted in said casing and adapted to impart sound vibrationsto the static column of air in said casing, a compensating weight vpivoted below the casing and arranged to bear upon the, record or recording surface, a stylus lever pivoted to the compensating weight,

1 connections between the stylus lever and said piston, anda tension device for imposing an elastic pressure of the stylus onvthe record or recording surface, substantially as and for the purposes set forth.

9. In a phonographic recording or reproducing device, the combination of a casing, a vibrating body, a compensating weight pivoted below the casing and arranged to bear uponthe record or recording surface, said weight being free to move the record or recording surface, substantially as and for the purposes set forth.

10. In a phonographic recording or reproducing device, the combination of a\casing, a vibrating piston freely mounted in said. casing, a compensating weight pivoted below the casing and arranged to bear upon the record or recording surface, a

stylus lever pivoted to the compensating weight, connections between the stylus lever and said piston, a stylus mounted 'on the lever and in line with the part of the compensating weight in engagement with the record or recording surface, and a tension device for imposing an elastic pressure of the stylus on the record or recording surface, substantially as and for the purposes set forth. a v

11. As a new article of manufacture, a vibrating piston for phonographic recording or reproducing apparatus, made of sheet metal with a depending peripheral flange having a rim at the bottom thereof at right angles to the flange and a corrugated main portion, substantially as and for the purposes set forth.

12. As a new article of manufacture, a vibrating .piston for phonographic' recording or reproducing apparatus,made of sheet metal havinga depending peripheral flange having a rim at the bottom thereof at right angles to the flange and radial ribs, substantially as and for the purposes set forth.

13. As a new article of manufacture, a vibrating piston for phonographic recording or reproducing apparatus, made of sheet metal with a depending peripheral flange having a rim at the bottom thereof at right angles to the flange and a corrugated main portion and provided with radial ribs, substantially as and for'the purposes set forth.

This specification signed and witnessed this 25th day of February 1907.

THOS. A. EDISON.

Witnesses:

FRANK L. DYER,

FRANK D. LEwIs. 

